Next since we are using that equation we know that the answer involved has a right angle it it somewhere.

Draw a picture of a right triangle then make it into a rectangle. Draw a line from corner to corner and going threw the other side(the size where the first right angle was)
http://img182.imageshack.us/img182/3530/pythaghelpvw8.png [Broken]

Then play around with the numbers and angles and see if you can come up with the same answer. I hope this helps you out a little bit! Although I am not exactly sure on how to solve it myself.